JP3969437B2 - Fluorine-containing elastomer composition - Google Patents

Description

The present invention relates to a fluorine-containing elastomer composition. More specifically, the present invention relates to a fluorine-containing elastomer having a halogenophenyl group as a crosslinkable group and a fluorine-containing elastomer composition comprising the crosslinking agent.

で表わされる2,2-ビス(メルカプトフェニル)ヘキサフルオロプロパン[2,2,2-トリフルオロ-1-(トリフルオロメチル)エチリデン-ビスベンゼンチオール]がポリサルファイドポリマーおよびコポリマーの前駆物質として有効に用いられることが、下記特許文献に記載されている。
米国特許第４，７２０，５９０号明細書 特表昭６０−５００１７５号公報 formula

2,2-bis (mercaptophenyl) hexafluoropropane [2,2,2-trifluoro-1- (trifluoromethyl) ethylidene-bisbenzenethiol] represented by the formula is effectively used as a precursor for polysulfide polymers and copolymers It is described in the following patent document.
US Pat. No. 4,720,590 JP-T-60-500195

  However, in these patent documents, there is no further description regarding the use of 2,2-bis (mercaptophenyl) hexafluoropropane.

  An object of the present invention is to find a novel use of 2,2-bis (mercaptophenyl) hexafluoropropane and to provide a fluorine-containing elastomer composition using this as a crosslinking agent for the fluorine-containing elastomer.

(ここで、Rfは炭素数1〜10のパーフルオロアルキリデン基である)で表わされるビスチオフェノールパーフルオロアルキリデン化合物架橋剤を含有する含フッ素エラストマー組成物によって達成される。 The object of the present invention is to provide 30 to 70 mol% tetrafluoroethylene, 65 to 25 mol% perfluoro (lower alkyl vinyl ether) or perfluoro (lower alkoxy lower alkyl vinyl ether) and 0.1 to 5 mol% halogenophenyl group. A fluorinated elastomer having a halogenophenyl group as a crosslinkable group and a general formula , which is a terpolymer comprising a vinyl ether compound

(Where Rf is a perfluoroalkylidene group having 1 to 10 carbon atoms) is achieved by a fluorine-containing elastomer composition containing a bisthiophenol perfluoroalkylidene compound crosslinking agent .

  According to the present invention, 2,2-bis (mercaptophenyl) hexafluoropropane was found to be effective as a crosslinking agent for a fluorine-containing elastomer having a halogenophenyl group, and a fluorine-containing elastomer composition comprising these components as essential components. Things are provided.

(ここで、Rfは炭素数1〜10のパーフルオロアルキリデン基である)で表わされるビス(クロロスルホニルフェニル)パーフルオロアルキリデン化合物を酸性条件下において亜鉛を用いて還元することによって、一般式

(ここで、Rfは前記定義と同じである)で表わされるビスチオフェノールAFとして得られる。 2,2-bis (mercaptophenyl) hexafluoropropane (bisthiophenol AF) used as a crosslinking agent for fluorine-containing elastomers has the general formula

(Wherein Rf is a perfluoroalkylidene group having 1 to 10 carbon atoms) a bis (chlorosulfonylphenyl) perfluoroalkylidene compound represented by the general formula is reduced with zinc under acidic conditions.

(Wherein Rf is the same as defined above) and is obtained as bisthiophenol AF.

は、出発物質としての2,2´-ビスフェニルヘキサフルオロプロパンを過剰モル数のクロロスルホン酸中に約0〜20℃で撹拌条件下に滴下し、滴下終了後約40〜100℃、好ましくは約50〜70℃で約1〜24時間加熱することにより、ほぼ定量的に取得することができる。 In the above formula [I], a perfluoroisopropylidene group is generally used as the perfluoroalkylidene group having 1 to 10 carbon atoms. In this case, the production method will be described. 2,2´-bis (3-chlorosulfonylphenyl) hexafluoropropane

2,2′-bisphenylhexafluoropropane as a starting material is dropped into an excess of chlorosulfonic acid at about 0 to 20 ° C. under stirring conditions, and about 40 to 100 ° C., preferably after completion of the dropwise addition. By heating at about 50-70 ° C. for about 1-24 hours, it can be obtained almost quantitatively.

  The 2,2′-bis (3-chlorosulfonylphenyl) hexafluoropropane thus obtained is a novel substance, which was dissolved in a solvent in which aromatic hydrocarbons such as benzene and toluene are preferably used. Thereafter, an excess molar number of zinc dust is added thereto, and the reaction is carried out under acidic conditions such as dropwise addition of concentrated hydrochloric acid. After completion of dropping, the mixture is stirred at about 40 ° C. or lower, preferably about 20 ° C. or lower for about 1 to 10 hours, preferably about 1 to 3 hours, and then about 50 to 100 ° C., preferably about 60 to 70 ° C. By heating for 10 hours, preferably about 2 to 3 hours, the reduction reaction of the chlorosulfonyl group to the mercapto group is completed. The yield in this step is about 60% or more.

The reaction product 2,2′-bis (3-mercaptophenyl) hexafluoropropane was newly found to be effectively used as a crosslinking agent for fluorine-containing elastomers having a halogenophenyl group as a crosslinking group . . This compound is also used as a dipotassium salt or the like, and is used at a general use ratio of about 0.1 to 5 parts by weight (in each example, 3 parts by weight) per 100 parts by weight of the fluorine-containing elastomer.

As the fluorine-containing elastomer having a halogenophenyl group as a crosslinkable group , about 30 to 70 mol% tetrafluoroethylene, about 65 to 25 mol% perfluoro (lower alkyl vinyl ether) or perfluoro (lower alkoxy lower alkyl vinyl ether) And a terpolymer comprising about 0.1 to 5 mol% of a halogenophenyl group-containing vinyl ether compound is used.

As perfluoro (lower alkyl vinyl ether), perfluoro (methyl vinyl ether) is generally used. Further, as perfluoro (lower alkoxy lower alkyl vinyl ether), for example, the following is used,
CF ₂ = CFOCF ₂ CF (CF ₃ ) OC _n F _{2n + 1} (n: 1 to 5)
CF ₂ = CFO (CF ₂ ) ₃ OC _n F _{2n + 1} (n: 1 to 5)
CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ O) _m C _n F _{2n + 1} (n: 1 to 5, m: 1 to 3)
CF ₂ = CFO (CF ₂ ) ₂ OC _n F _{2n + 1} (n: 1 to 5)
Of these, those in which the C _n F _{2n + 1} group is a CF ₃ group are particularly preferred.

X：ハロゲン原子
n：1〜5の整数
Further, as the halogenophenyl group-containing vinyl ether compound as the crosslinking site monomer , the following can be used.

X: Halogen atom
n: Integer from 1 to 5

Such a vinyl ether compound is obtained by adding chlorine or bromine (Y) to CF ₂ = CFO (CF ₂ ) nCOOR, hydrolyzing the resulting CF ₂ YCFYO (CF ₂ ) nCOOR, and performing an acid chloride reaction. after reacting with halogenobenzene, a -CO- is reacted with SF ₄ -CF ₂ - is transformed into a method or _{CF 2 = CFO (CF 2)} nCOOR hydrolysis and acid to dechlorination or debromination reaction It is produced by a method of performing a chlorination reaction, reacting it with monohalogenobenzene, and then reacting with SF ₄ to convert —CO— to —CF ₂ .

  In the terpolymers having the above components as essential components, fluorinated olefins, olefins, vinyl compounds, etc. that do not inhibit the copolymerization reaction and do not impair the vulcanization properties (about 20 mol% or less) It can also be copolymerized.

  In preparation of the composition, in addition to each of the above essential components, a crosslinking aid such as a quaternary phosphonium salt, an acid acceptor such as magnesium oxide, and other necessary components are appropriately added, and a two-roll rubber mill or the like is added. After kneading, vulcanization conditions applied to this type of fluorine-containing elastomer, that is, press vulcanization (primary vulcanization) at about 150 to 250 ° C. for about 5 to 60 minutes (180 ° C. for 30 minutes in each example) ), And then vulcanization is performed by oven vulcanization (secondary vulcanization) at about 200 to 300 ° C. for about 24 to 72 hours in an inert gas atmosphere such as a nitrogen gas atmosphere. Oven vulcanization (secondary vulcanization) is preferably performed while gradually increasing the vulcanization temperature. In each example, the temperature is increased from 90 ° C. for 4 hours and then from 90 ° C. to 204 ° C. over 6 hours. Thereafter, the temperature is raised from 204 ° C. for 18 hours and then from 204 ° C. to 288 ° C. over 6 hours, and then oven vulcanization (secondary vulcanization) is performed at 288 ° C. for 18 hours.

  Next, the present invention will be described with reference to examples.

Reference Example To a reaction vessel charged with 85 g (0.73 mol) of chlorosulfonic acid, 27 g (0.09 mol) of 2,2′-bisphenylhexafluoropropane was added dropwise at 10-12 ° C. over 15 minutes under stirring conditions. After completion of the dropwise addition, the mixture was heated at 50 ° C. for 3 hours and then poured into ice water to separate the solid residue. 2,2′-bis (3-chlorosulfonylphenyl) hexafluoropropane was obtained almost quantitatively.

純度：83%(ヨウ素酸化滴定法による)
元素分析：
実測値；C 48.96%、H 2.70%、F 31.09%
計算値；C 48.91%、H 2.72%、F 30.98% In a reaction vessel charged with a mixture of 50 g (0.1 mol) of 2,2′-bis (3-chlorosulfonylphenyl) hexafluoropropane dissolved in 180 ml of benzene and 96.5 g (1.48 mol) of zinc powder, 380 ml of concentrated hydrochloric acid was added. It was dripped under stirring conditions. During this time, the temperature of the reaction mixture was not allowed to rise above 20 ° C. The mixture was heated at 20 ° C. for 2 hours, then at 60-70 ° C. for 3 hours, cooled to room temperature, and the reaction product was extracted with benzene. The extract was washed with 300 ml of a degassed aqueous solution in which 0.5 g of Na ₂ S ₂ O ₄ was dissolved, benzene was distilled off, and 2,2′-bis (3-mercaptophenyl) hexafluoropropane [bisthiophenol AF ] 22.95 g (yield 62.3%) was obtained.

Purity: 83% (Iodine oxidation titration method)
Elemental analysis:
Found: C 48.96%, H 2.70%, F 31.09%
Calculated value: C 48.91%, H 2.72%, F 30.98%

Ｂ：次式で示されるビス-ジサルファイド型の分子イオンと考えられる

Note) A: It is considered to be a bis-thiol type molecular ion represented by the following formula

B: It is considered to be a bis-disulfide type molecular ion represented by the following formula

Example 1
Tetrafluoroethylene-perfluoro (methyl vinyl ether) -4- (4'-fluorophenyl) -perfluoro (butyl vinyl ether) (molar ratio 63.2: 35.3: 1.5) terpolymer [perfluoro (2-butyltetrahydrofuran) Reduced viscosity ηsp / c measured at 35 ° C. for a 1 wt% solution of 1.86 ml / g] to 100 parts by weight,
MT carbon black 20 parts by weight Bisthiophenol AF dipotassium salt 3 〃
Benzyltriphenylphosphonium chloride 1 〃
Magnesium oxide 4 〃
Kneaded on a two-roll rubber mill, and the kneaded product was press vulcanized (primary vulcanization) at 180 ° C. for 30 minutes, and then oven vulcanized under the following heating conditions in a nitrogen gas atmosphere (Secondary vulcanization) was performed. In addition, an increase in the vulcanization torque was observed only with the primary vulcanization, and the progress of the vulcanization reaction was confirmed.
4 hours at 90 ° C
Heating from 90 ° C to 204 ° C over 6 hours
18 hours at 204 ℃
Heated from 204 ° C to 288 ° C over 6 hours
18 hours at 288 ° C

  When the compression set at 200 ° C. or 250 ° C. was measured for the obtained vulcanized molded product, values of 66% and 68% were obtained, respectively.

  The tetrafluoroethylene-perfluoro (methyl vinyl ether) -4- (4′-fluorophenyl) -perfluoro (butyl vinyl ether) terpolymer used in this example was produced as follows. It was.

After charging 1.8L of distilled water, 23.7g of ammonium perfluorooctanoate, 14.3g of Na ₂ HPO ₄ · 12H ₂ O and 0.67g of NaH ₂ PO ₄ · 2H ₂ O into a 3L stainless steel autoclave, Was purged with nitrogen and then depressurized. Then, 25 g of tetrafluoroethylene, 55 g of perfluoro (methyl vinyl ether) and 7.2 g of 4- (4′-fluorophenyl) -perfluoro (butyl vinyl ether) were sequentially added and heated to 50 ° C., and then sodium sulfite 1.66 g and 9.08 g of ammonium persulfate were charged as 50 ml aqueous solutions, respectively, to initiate the polymerization reaction.

During the polymerization reaction, tetrafluoroethylene at a flow rate of 12.8 g / hr, perfluoro (methyl vinyl ether) at 16.5 g / hr, and 4- (4′-fluorophenyl) -perfluoro (butyl vinyl ether) at a flow rate of 2.2 g / hr. In addition, the pressure in the autoclave was maintained at 9 kg / cm ² G. After 19 hours from the start of polymerization, the addition was stopped, and the state was maintained for 1 hour. The autoclave was cooled, the residual gas was purged, and an aqueous latex having a solid content concentration of 20% by weight was taken out.

The removed aqueous latex was added to 20 L of saturated saline at 70 ° C. to coagulate the produced polymer. The coagulated product was filtered and washed with water, followed by drying at 70 ° C. under normal pressure for 12 hours to 120 ° C. under reduced pressure for 12 hours to obtain 560 g of a white rubbery terpolymer. The infrared absorption spectrum, absorption was observed at 1520 cm ^-1 and 1615 cm ^-1, perfluoro in the copolymer [4- (4'-fluorophenyl) butyl vinyl ether] that is copolymerized was confirmed.

Example 2
Tetrafluoroethylene-perfluoro (methyl vinyl ether) -4- (4'-chlorophenyl) -perfluoro (butyl vinyl ether) (molar ratio 72.8: 25.7: 1.5) of the terpolymer [perfluoro (2-butyltetrahydrofuran)] Reduced viscosity ηsp / c measured at 35 ° C for a 1 wt% solution: 1.80 ml / g]
MT carbon black 20 parts by weight Bisthiophenol AF dipotassium salt 3 〃
Benzyltriphenylphosphonium chloride 1 〃
Magnesium oxide 4 〃
After kneading on a two-roll rubber mill, the kneaded product was subjected to press vulcanization (primary vulcanization) at 180 ° C for 30 minutes, and then oven vulcanized under the following heating conditions in a nitrogen gas atmosphere ( Secondary vulcanization) was performed. In addition, an increase in the vulcanization torque was observed only with the primary vulcanization, and the progress of the vulcanization reaction was confirmed.
4 hours at 90 ° C
Heating from 90 ° C to 204 ° C over 6 hours
18 hours at 204 ℃
Heated from 204 ° C to 288 ° C over 6 hours
18 hours at 288 ° C

  When the compression set at 200 ° C. or 250 ° C. was measured for the obtained vulcanized molded product, values of 48% and 57% were obtained, respectively.

  The tetrafluoroethylene-perfluoro (methyl vinyl ether) -4- (4′-chlorophenyl) -perfluoro (butyl vinyl ether) terpolymer used in this example was produced as follows. .

A 3 L stainless steel autoclave was charged with 1.7 L of distilled water, 54.6 g of ammonium perfluorooctanoate and 23.7 g of KH ₂ PO ₄ .2H ₂ O, and then the interior was purged with nitrogen gas, and then the pressure was reduced. Then, 31 g of tetrafluoroethylene, 45 g of perfluoro (methyl vinyl ether) and 5.6 g of 4- (4′-chlorophenyl) -perfluoro (butyl vinyl ether) were sequentially added and heated to 60 ° C., and then 0.18 g of sodium sulfite Then, 1.0 g of ammonium persulfate was charged as a 50 ml aqueous solution, and the polymerization reaction was started.

During the polymerization reaction, tetrafluoroethylene was separated at a flow rate of 9.6 g / hr, perfluoro (methyl vinyl ether) at 9.6 g / hr, and 4- (4′-chlorophenyl) -perfluoro (butyl vinyl ether) at a flow rate of 0.94 g / hr. In addition, the pressure in the autoclave was kept at 9 kg / cm ² G. After 5 hours and 6 minutes from the start of polymerization, the addition was stopped, and the state was maintained as it was for 1 hour. The autoclave was cooled and the residual gas was purged to take out an aqueous latex having a solid content concentration of 10.6% by weight.

The removed aqueous latex was added to 20 L of saturated saline at 70 ° C. to coagulate the produced polymer. The coagulated material was filtered and washed with water, followed by drying at 70 ° C. under normal pressure for 12 hours to 120 ° C. under reduced pressure for 12 hours to obtain 125 g of a white rubbery terpolymer. The infrared absorption spectrum, absorption was observed at 1490cm ^-1 and 1600 cm ^-1, perfluoro in the copolymer [4- (4'-chlorophenyl) butyl vinyl ether] that is copolymerized was confirmed.

Claims (1)

A ternary composition comprising 30 to 70 mol% tetrafluoroethylene, 65 to 25 mol% perfluoro (lower alkyl vinyl ether) or perfluoro (lower alkoxy lower alkyl vinyl ether) and 0.1 to 5 mol% halogenophenyl group-containing vinyl ether compound Fluorine-containing elastomer having a halogenophenyl group as a crosslinkable group and a general formula , which is a copolymer

A fluorine-containing elastomer composition comprising a bisthiophenol perfluoroalkylidene compound crosslinking agent represented by the formula (wherein Rf is a C 1-10 perfluoroalkylidene group).